The present invention relates to cable splicing and, more particularly, to an apparatus and method for splicing cables using magnetic pulse forming or magnetic pulse welding techniques.
Stranded cables are manufactured by twisting multiple wire strands around one another. A length of the stranded cable is then wrapped around a spool, and shipped to the end user. The end user, at times, must splice together two or more lengths of cable in order to fabricate a cable of sufficient length as may be required for a specific application one technique for splicing pieces of cable together involves inserting respective ends of two cables into a splice band and mechanically crimping the splice band from three equally spaced directions, one hundred and twenty degrees apart.
One of the problems associated with this splicing process is the inconsistency in engaging the fibers in the splice band. Very often the band does not contact all of the fibers disposed about the entire three hundred and sixty degrees of the banded joint. Generally, it is observed that there is better engagement of the fibers at the center of the crimped areas of the band, which are located sixty degrees apart. As a result, the strength of the joint is usually not uniform.
In accordance with the present invention, there is provided a method and apparatus for uniformly splicing stranded cables. A joint for a stranded cable can be formed by inserting the ends of two cables into an electrically conductive splice band which, in turn, is inserted into a coil or inductor. The splice is fabricated by a process known as magnetic pulse forming, or magnetic pulse welding, wherein a very large electrical current pulse of short duration is directed through the coil or inductor from a charged capacitor bank. The resulting magnetic field in the coil or inductor creates an induced magnetic field on the splice band, compressing the splice band uniformly around the circumference of the two cable ends being spliced. In the case of magnetic pulse welding, the splice band not only uniformly compresses the stranded cables but a weld is also created between the inner diameter of the sleeve and the adjacent stranded cables. A field shaper can be interposed between the electrical coil or inductor, and the splice band in order to focus the imposed magnetic forces in a specific region or regions of the splice band. A variation of this approach is to provide a split in the coil/field shaper combination or the inductor so as to form semicircular segments to allow removal from a completed spliced wire. This would be required typically in the case of a wire spliced between two existing wires. Concentrators may be incorporated into the field shaper to increase the magnetic flux in localized areas of the splice band.
It is an object of this invention to provide an improved splice method and apparatus.
It is another object of the invention to provide a uniform splice by means of magnetic pulse forming or magnetic pulse welding.